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Analysis of the Performance of Disc Brake System of Addis Ababa Light Rail Transit Using Temperature and Coefficient of Friction as a Parameter
Issue:
Volume 4, Issue 6, December 2016
Pages:
205-211
Received:
30 September 2016
Accepted:
14 October 2016
Published:
16 November 2016
Abstract: Most of railroad passenger vehicles in the world equipped with disc brake system which is mounted either on the wheel for (wheel mounted) or axle on the bogie frames for (axle mounted). A disc brake is a device which is used to stop or reduce the motion of vehicles. The braking performance of the train is one of the most important factors that affect the traffic and running safety of the vehicle. Among many factors, braking performance of trains is mainly affected by temperature and µ (between brake disc and pad). The main purpose of this study is determination of nodal temperature and friction coefficient, considering different loading and operating conditions, necessary to verifying safety requirements for the movement of trains. Disc brake is modeled on Solid Works 13.0, then simulation was followed using Multi-physics ANSYS workbench 14.5 Version. The thermal transient analysis of disc braking system is performed to evaluate under service and emergency braking conditions independently for selected stations. A comparison between analytical determination of µ and Ansys analysis results shows that, the performance of the disc brake is highly affected during emergency braking conditions due to minimum stopping distance and delay time. The analysis result shows, compare to the 3 stations, the maximum nodal temperature is 413.88°C at station Meri/CMC 2 which is much less than from the allowable values of 800°C. The results obtained by the simulation are satisfactory compared with those of the specialized literature Hence, a good suggestion will be given on the vehicle travelling speed based on the performance on each braking conditions where if results is obtained above the allowable value.
Abstract: Most of railroad passenger vehicles in the world equipped with disc brake system which is mounted either on the wheel for (wheel mounted) or axle on the bogie frames for (axle mounted). A disc brake is a device which is used to stop or reduce the motion of vehicles. The braking performance of the train is one of the most important factors that affe...
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Artificial Neural Network Approach for Transient Forced Convective Heat Transfer Optimization
Issue:
Volume 4, Issue 6, December 2016
Pages:
212-225
Received:
29 October 2016
Accepted:
16 November 2016
Published:
23 November 2016
Abstract: This present research uses artifical neural networks (ANNs) to analyze and estimate the influence of transfer functions and training algorithms on experimentally determined Nusselt numbers, friction factors, entropy generation numbers and irreversibility distribution ratios for nine different baffle plate inserted tubes. Nine baffle-inserted tubes have several baffles with various geometric parameters used in the experiments with a baffle area blockage ratio of two, with different pitch to diameter ratios, different baffle orientation angles and different baffle spacings. The actual experimental data sets were used from previous author’s studies and applied as a input data set of ANNs. MATLAB toolbox was used to search better network configuration prediction by using commonly used multilayer feed-forward neural networks (MLFNN) with back propagation (BP) learning algorithm with thirteen different training functions with adaptation learning function of mean square error and TANSIG transfer function. In this research, eighteen data samples were used in a series of runs for each nine samples of baffle-inserted tube. Reynold number, tube lenght to baffle spacing ratio, baffle orientation angle and pitch to diameter ratio were considered as input variables of ANNs and the time averaged values of Nusselt number, friction factor, entropy generation number and irreversibility distribution ratio were determined as the target data. The total 70% of the experimental data was used to train, 15% was used to test and the rest of data was used to check the validity of the ANNs. The TRAINBR training function was found as the best model for predicting the target experimental outputs. Almost perfect accuracy between the neural network predictions and experimental data was achieved with mean relative error (MRE) of 0,000105816% and correlation coefficient (R) that was 0,999160176 for all datasets, which suggests the reliability of the ANNs as a strong tool for predicting the performance of transient forced convective heat transfer applications.
Abstract: This present research uses artifical neural networks (ANNs) to analyze and estimate the influence of transfer functions and training algorithms on experimentally determined Nusselt numbers, friction factors, entropy generation numbers and irreversibility distribution ratios for nine different baffle plate inserted tubes. Nine baffle-inserted tubes ...
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Generalized Synchronization of Fractional Order Chaotic Systems with Time-Delay
Sha Wang,
Jie Li,
Renhao Jin
Issue:
Volume 4, Issue 6, December 2016
Pages:
232-241
Received:
22 July 2016
Accepted:
27 October 2016
Published:
17 December 2016
Abstract: Generalized synchronization of time-delayed fractional order chaotic systems is investigated. According to the stability theorem of linear fractional differential systems with multiple time-delays, a nonlinear fractional order controller is designed for the synchronization of systems with identical and non-identical derivative orders. Both complete synchronization and projective synchronization also can be realized based on the proposed controller. The effectiveness and robustness of the controller are verified in the numerical simulations.
Abstract: Generalized synchronization of time-delayed fractional order chaotic systems is investigated. According to the stability theorem of linear fractional differential systems with multiple time-delays, a nonlinear fractional order controller is designed for the synchronization of systems with identical and non-identical derivative orders. Both complete...
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Applicability of the Hertz Contact Theory to Rolling Rubber Cylinders Model
Chu Hongyan,
An Ran,
Cai Ligang
Issue:
Volume 4, Issue 6, December 2016
Pages:
242-248
Received:
24 December 2016
Published:
28 December 2016
Abstract: Hertz contact theory (HCT) is a study of contact stress and deformation which is widely used in many engineering fields. However, there are many limiting conditions for the applications of the HCT, in this paper, the contact model between a plastic cylinder and a rubber cylinder does not fit two limiting conditions: Small deformation and no rigid body motion. By applying three-dimensional finite element models, the deformation and the maximum contact stress of two rotating cylinders have been analyzed. Comparing the simulation results and the theoretical results, the applicability of Hertz contact theory to this model has been discussed. The results show that: In the condition of large deformation, the theoretical results of maximum contact stress fit the actual situation, but the half-width of the contact area does not fit. Under the rolling condition, the theoretical maximum contact stress has a large deviation to simulation result.
Abstract: Hertz contact theory (HCT) is a study of contact stress and deformation which is widely used in many engineering fields. However, there are many limiting conditions for the applications of the HCT, in this paper, the contact model between a plastic cylinder and a rubber cylinder does not fit two limiting conditions: Small deformation and no rigid b...
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Quantitative and Controllable Growth of Carbon Nanotubes on Silicon Carbide Particles Via Chemical Vapor Deposition
Huiling Jin,
Jia Jianjun,
Yishi Su,
Shisheng Li,
Qiubao Ouyang,
Di Zhang
Issue:
Volume 4, Issue 6, December 2016
Pages:
249-253
Received:
16 October 2016
Accepted:
19 December 2016
Published:
19 January 2017
Abstract: Carbon nanotube (CNT) and silicon carbide particles (SiCp) can work together as a double-scale hybrid reinforcement for new metal matrix composites. In this paper, nano nickel (Ni) particle catalyst was precipitated by carbamide to achieve uniform dispersion on micron SiCp. And then a CNT-covered SiCp hybrid was synthesized by a conventional Chemical Vapor Deposition (CVD) method. We found that the content of Ni catalyst has great effects on the size and production of CNT. The yield of CNT reached 20.73 wt.% with 5.0 wt.% Ni under the condition of 923 K and 1 h for CVD process. The diameter and average length of the as-grown CNT are 20~30 nm and 3 μm, respectively. Meantime, the chemistry during the controllable growth of CNT was analyzed on the basis of experimental results.
Abstract: Carbon nanotube (CNT) and silicon carbide particles (SiCp) can work together as a double-scale hybrid reinforcement for new metal matrix composites. In this paper, nano nickel (Ni) particle catalyst was precipitated by carbamide to achieve uniform dispersion on micron SiCp. And then a CNT-covered SiCp hybrid was synthesized by a conventional Chemic...
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